Are you struggling with removing whitespace from plot borders in images generated by the imshow() function in Matplotlib? Don’t worry, you’re not alone! Many users face this issue when trying to animate plots. In this blog post, we will explore different methods to tackle this problem and achieve the desired result.
Why won’t the usual methods work?
You may have tried using tight_layout() or subplots_adjust() functions to remove the whitespace, but unfortunately, these methods didn’t yield the desired outcome. Even alternative approaches suggested in various Stack Overflow posts may not have provided the complete solution. However, fear not, as we have some more techniques up our sleeves!
Adjusting the figure and axes
One potential solution involves adjusting the figure and axes parameters. Start by setting the facecolor of the figure to a distinct color, such as purple, to visualize the boundaries clearly. Here’s an example code snippet:
import matplotlib.pyplot as plt
import numpy as np
fig, ax = plt.subplots(facecolor=’purple’)
fig.subplots_adjust(left=0, bottom=0, right=1, top=1, wspace=None, hspace=None)
ax.margins(0, 0)
plt.gca().xaxis.set_major_locator(plt.NullLocator())
plt.gca().yaxis.set_major_locator(plt.NullLocator())
img = ax.imshow(np.random.normal(0, 2, (200, 200)), animated=True)
With this approach, you should be able to eliminate most of the whitespace. However, in some cases, there might still be a small portion visible. The purple background color helps identify where the figure ends and any remaining whitespace persists.
Fine-tuning the parameters
Another technique involves adjusting the subplots_adjust() function’s arguments. Set the values of top, bottom, right, left, hspace, and wspace to zero. Here’s an example code snippet:
import matplotlib.pyplot as plt
import numpy as np
fig, ax = plt.subplots()
plt.subplots_adjust(top=1, bottom=0, right=1, left=0, hspace=0, wspace=0)
ax.margins(0, 0)
img = ax.imshow(np.random.normal(0, 2, (200, 200)), animated=True)
Considerations for Spyder IDE
If you’re using the Spyder IDE, it’s worth noting that it may have some additional idiosyncrasies that can affect the plot display. To ensure optimal results, you can adjust the IDE’s settings. Navigate to Preferences > IPython console > Graphics and uncheck the option for “Use a tight layout for inline plots.” This adjustment will align the plots according to your desired specifications.
Using the extent parameter
Another approach to remove whitespace from plot borders is by utilizing the extent parameter of the imshow() function. This parameter allows you to specify the extent of the image data, effectively cropping out any unwanted whitespace. Here’s an example:
import matplotlib.pyplot as plt
import numpy as np
data = np.random.normal(0, 2, (200, 200))
extent = [0, data.shape[1] , 0, data.shape[0]
plt.imshow(data, extent=extent, animated=True)
plt.axis(‘off’)
By setting the extent parameter to the dimensions of your data, you ensure that the plot covers the entire image, leaving no whitespace around the borders. Additionally, calling plt.axis('off') removes the axes, further enhancing the clean appearance of the plot.
Customizing the figure size and DPI
Sometimes, the whitespace issue can be resolved by adjusting the figure size and DPI (dots per inch). By specifying these parameters explicitly, you can control the dimensions and resolution of the plot, potentially eliminating unwanted whitespace. Here’s an example:
import matplotlib.pyplot as plt
import numpy as np
data = np.random.normal(0, 2, (200, 200))
fig = plt.figure(figsize=(5, 5), dpi=100)
plt.imshow(data, animated=True)
plt.axis(‘off’)
By experimenting with different values for figsize and dpi, you can find the optimal combination that eliminates whitespace and produces the desired plot size and resolution.
Adjusting the subplot margins
In some cases, adjusting the subplot margins can help remove whitespace. By setting the margins to zero, you can minimize any extra space surrounding the plot. Here’s an example:
import matplotlib.pyplot as plt
import numpy as np
data = np.random.normal(0, 2, (200, 200))
fig, ax = plt.subplots()
ax.imshow(data, animated=True)
ax.margins(0)
plt.axis(‘off’)
Conclusion
Removing whitespace from plot borders in Matplotlib’s imshow() output can be a perplexing task, but with the right techniques, you can achieve the desired outcome. By adjusting the figure and axes parameters or fine-tuning the subplots_adjust() function’s arguments, you can eliminate most, if not all, of the whitespace. Keep in mind any potential idiosyncrasies of your IDE, such as the Spyder environment, and make the necessary adjustments for optimal results.we explored additional techniques to remove whitespace from plot borders in Matplotlib’s imshow() output. By utilizing the extent parameter, customizing the figure size and DPI, adjusting subplot margins, and fine-tuning the plot settings, you have a range of methods to achieve a clean and whitespace-free plot. Experiment with these techniques, and don’t be afraid to combine them to achieve the best results for your specific case. Remember, removing whitespace can greatly enhance the visual appeal and focus of your plots, providing a more professional and polished look.
